Device for forming by carding one or more fleeces of fibres, in particular non-woven

ABSTRACT

Device for forming by carding one or more fleece(s) of fibres comprising a main carding drum ( 1 ) supplied with raw fibres, one or more doffer cylinder(s) ( 3 ) capable of removing the fibres worked on the carding drum and an associated stripper roller to strip the fleece(s) of fibres formed on the or each doffer and deposit them on one or more output belts, the device also comprising at least one comb-cleaner flywheel ( 4 ) capable of interacting with at least one doffer cylinder to remove dust and impurities therefrom, characterised in that it/they is/are fitted with prevention means ( 3, 4 ) which are configured so as to prevent the dust and impurities removed from the comb by the cleaner flywheel from escaping in the direction of the associated stripper roller.

The present invention relates to a device for forming one or more fleece(s) of fibres, in particular non-woven, by carding.

Traditionally, a device for forming a fleece of fibres by carding comprising a main carding drum supplied with raw fibres which carries out the actual carding. The device also comprises one or more doffers suitably arranged to collect the fibres on the main drum to create fleece(s) of fibres after stripping the fibres from the doffer(s) by a stripper roller depositing the fleece(s) of fibres on a respective output belt.

Traditionally, a device EP 0 972 865 A1 was known for forming a fleece of fibres by carding, comprising a main carding drum 104 from which the fibres were then collected by a doffer 107 in the form of a fleece by a stripper roller 46. This document also describes a device for cleaning the stripper seal with a brush to remove dust, small fibres and other impurities.

A device EP 0 143 925 A1, of the same type, was also known comprising a doffer 1, from whose surface a fleece V of fibres was detached by a stripper roller 2, the fleece then being transferred between two pressure rollers 4 and 40, and then to a conveyor belt 5. This document describes a cleaner flywheel 3 to clean the outer surface of the stripper, in particular the small fibres that are separated from the fleece, dust and other impurities. Furthermore, a suction device 6 is provided to draw in the impurities collected from the stripper 2. by the cleaner flywheel 3

Traditionally, a device of this type, for example the EP 3 473 753 A1, was also known. The device described herein comprises a doffer cleaner to clean the doffer trim, in particular the dust and impurities created by the carding process.

Even though EP 3 473 753 A1 aimed to make the fleece of fibres produced at the output more uniform and pierced with fewer holes made by the cleaning carried out by the cleaner roller; however, it is desired to produce a fleece of fibres of higher quality and, in particular, even more uniform and with fewer holes.

According to the invention, a device for forming by carding one or more fleece(s) of fibres comprising a main carding drum supplied with raw fibres, one or more doffer(s) to strip the worked fibres from the carding drum and one or more associated stripper rollers to remove the fleece(s) of fibres formed on the, or each doffer and deposit them later on one more output belts, the device also comprises at least one doffer cleaner flywheel working in conjunction with the, or at least one, doffer doffer to remove dust and impurities, and characterised in that prevention means are arranged to prevent dust and impurities removed from the doffer by the cleaner flywheel from escaping in the direction of the associated stripper roller.

By thus preventing damaged fibres and other dust removed from the doffer by the cleaner flywheel during the removal of impurities and other dust from escaping towards the stripper roller and contaminating it, we can ensure that the fleece(s) of fibres detached and deposited on the output belt(s) of the device for forming the fleece of fibres are not damaged by impurities and other dust deposited on the stripper roller, thereby creating non-homogeneity and holes in the fleece(s) of fibres. In this way, a very uniform fleece of fibres with very few, or even no holes is produced.

According to a first beneficial method of implementation, the prevention means comprise a screen placed between the cleaner flywheel/doffer and stripper roller interface, in particular within a housing essentially enclosing the cleaner flywheel.

According to another particularly beneficial method of implementation, in particular beneficially eliminating the need to provide a screen or enclosure, the prevention means are that the cleaner flywheel is driven in such a direction that any impurities or dust collected at the cleaner/carding interface are sent from this interface directly to the main carding drum.

In particular, according to a beneficial method of implementation, the doffer and its associated cleaner flywheel are driven in opposite directions.

According to a preferred method of implementation, the doffer rotates in the opposite direction to the carding drum and the cleaner flywheel rotates in the same direction as the carding drum.

In particular, there could be two doffers, upper and lower respectively, each comprising a respective cleaner flywheel and stripper roller.

Preferably, there will be one cleaner flywheel for the carding drum, in particular arranged upstream of the doffer(s).

Preferably, the device, together with the drum cleaner flywheel, will comprise at least one airtight roller upstream of the drum cleaner flywheel, in particular two airtight rollers, upstream and downstream respectively of the drum cleaner flywheel, the one or two airtight rollers and the carding drum cleaner flywheel rotating preferably in the same direction, in particular in the opposite direction to the carding drum.

In the case of a doffer situated at the top, or upper doffer, when the device comprises a drum cleaner flywheel and at least one downstream airtight roller, there is an intermediate roller, in particular smooth, placed between the carding drum and the said doffer, in particular below the downstream airtight roller to prevent a vacuum causing turbulence which would entrain accumulated fibres and dust likely to result in faults on the fleece formed.

Preferably, the downstream airtight roller would be arranged to brush the doffer cleaner flywheel, in particular rotating in the same direction as the latter.

According to a favoured method of implementation, the device comprises two doffers, upper and lower respectively, two doffer cleaner flywheels upper and lower respectively, in particular the upper doffer cleaner flywheel rotating in the opposite direction to that of the upper doffer and the lower doffer cleaner flywheel rotating in the opposite direction to the doffer, in particular the two doffers rotating in the same direction, and the two stripper rollers, upper and lower respectively, and there is also an upper doffer cleaner flywheel arranged upstream of the doffer and at least one upper, airtight roller downstream of the flywheel drum cleaner, preferably two airtight rollers, upper and lower respectively upstream and downstream of the doffer cleaner flywheel.

Preferably, the device comprises an intermediate roller, in particular smooth, placed between the upper drum and the doffer, below the upper doffer flywheel cleaner and below the upper downstream airtight roller.

Preferably, the device comprises a lower airtight roller placed between the lower doffer and the carding drum, the lower airtight roller being arranged to brush the lower doffer cleaner flywheel, in particular rotating in the opposite direction to the latter.

As an example, we now describe preferred methods of implementation of the invention with reference to drawings in which:

FIG. 1 is a diagrammatic side view of a fleece forming device according to a first method of implementation of the invention;

FIG. 2 is a diagrammatic side view of a fleece forming device comprising an upper doffer and a lower doffer to form two fleeces of fibres, upper and lower respectively;

FIG. 3 is a diagrammatic side view of another method of implementation of a device according to the invention; and

FIG. 4 is a diagrammatic side view of another method of implementation of a device according to the invention.

FIG. 1 shows a first method of implementation of the invention. A carding roller 1 is supplied with raw fibres by a feed cylinder (not shown in the diagram). Traditionally, the carding drum comprises a covering equipped with spikes to perform the actual carding. A doffer 3 is placed at the top of the carding drum to collect the fibres worked by the carding drum. The doffer thereby forms a fleece of fibres, for example non-woven, the fleece being collected by a stripper roller 7 placed on the opposite side of the carding drum with respect to the doffer, the stripper roller 7 detaching the fleece of fibres from the doffer and depositing it on an output belt of the device (belt not shown in the diagrams).

The device according to the invention in FIG. 1 also comprises a cleaner flywheel or roller 4 placed on the top of the doffer and arranged so as to bear against the doffer spikes to remove impurities and other dust from it. Traditionally, the doffer flywheel cleaner 4 has flexible spikes forming a brush, while the doffer has rigid spikes.

FIG. 1 , the carding drum 1 rotates in a clockwise direction (this is when it is fitted on the left in relation to the output belt). The doffer cylinder rotates anticlockwise, that is in the opposite direction to the carding drum. The doffer cleaner flywheel rotates in the same direction as the carding drum and in the opposite direction to the doffer, so that at the interface between the doffer 3 and the doffer cleaner flywheel 4, the peripheral speeds of the flywheel and the doffer are in the same direction, that is in the direction of the carding drum opposite to it.

The device in FIG. 1 also comprises a smooth roller 5 placed between the carding drum 1 and the doffer cylinder 3 and below the doffer cleaner flywheel 4. The purpose of the smooth roller is to prevent a vacuum causing turbulence that can cause faults in the fleece formed.

The device also comprises a drum cleaner flywheel 9 rotating in the opposite direction to the drum, and two airtight rollers 10 with rigid seals upstream and downstream respectively of the drum cleaner flywheel 9, located on each side of the cleaner flywheel 9. An enclosure 20 blocks emissions from the cleaner flywheel 9. However, it is not necessary to provide enclosures for the airtight rollers.

The downstream airtight roller 10 is located firstly above the smooth roller 5 and secondly so that its seal bears on, in particular brushes, the circumference of the doffer cleaner flywheel 4. The two airtight rollers 10 and the cleaner drum flywheel 9 rotate in the same direction as the doffer cylinder 3 and in the opposite direction to the drum and the doffer cleaner flywheel 4.

Traditionally, when a drum cleaner flywheel 9 is used, the speed of rotation of the main drum may be between 750 and 1,100 m/min and the speed of rotation (tangential or peripheral speed) of the doffer between 0 and 250 m/min, while the speed of rotation (tangential or peripheral speed) of the doffer cylinder cleaner may be between 0 and 230 m/min and the speed of rotation of the stripper roller may be between 0 and 400 m/min. Regarding the ratio of the peripheral speed of the doffer cleaner flywheel and the peripheral speed of the doffer, this can be such that the speed of the cylinder cleaner is 5 to 30 times less than the speed of the doffer in the case where the two cylinders rotate in opposite directions. Traditionally, the peripheral speed of the doffer is lower than the peripheral speed of the carding drum, in particular the ratio of the two speeds is between 5 and 100.

FIG. 2 shows a method of implementation of a device for forming two fleeces of fibres, upper and lower respectively, comprising a carding drum 1 and two doffers, 3 upper and 3′ lower.

The arrangement of the upper doffer 3 is the same as that shown in FIG. 1 , the device comprising at the top the same components as the device shown in FIG. 1, in particular the drum cleaner flywheel 9, the two upstream and downstream airtight rollers, the doffer cleaner flywheel and the smooth roller.

At the bottom, there is a cleaner flywheel 4′ and a stripper roller 7′ in an identical arrangement to that shown in FIG. 1 for the upper doffer. On the other hand, at the bottom there is no drum cleaner flywheel nor the associated airtight cylinders, nor the lower smooth roller between the drum 1 and the doffer 3′. The carding drum 1 rotates clockwise (when it is on the left in relation to the output belt). The rollers 3 and doffer 3′ rotate anticlockwise, that is, in the opposite direction to the carding drum. The doffer cleaner flywheels 4 and 4′ rotate in the same direction as the carding drum and in the opposite direction to the doffers, so that at the interfaces between the doffer 3′ and the doffer cleaner flywheel 4′, the peripheral speeds of the flywheel and the doffers are in the same direction, that is in the direction of the carding drum opposite to it. An airtight roller 10′ is arranged between the carding drum 1 and the lower doffer 3′ arranged so that the seal bears against, in effect brushes the periphery of the lower doffer cleaner flywheel 4′. The lower airtight roller 10′ rotating in the same direction as the lower doffer 3′ and in the opposite direction to that of the drum 1 and the lower doffer cleaner flywheel 4′.

FIG. 3 shows another method of implementation of a device according to the invention. The device comprises a carding drum 1 supplied by a feed roller 2, a doffer 3′, a stripper roller 7′ and a doffer cleaner flywheel 4″ coupled to an airtight flywheel 10″, arranged between the carding drum 1 and the comb 3′, so that its seal bears against, in effect brushes the periphery of the doffer cleaner flywheel 4″.

The doffer cleaner roller 4″ and the doffer 3′ rotate in the same direction. In particular, the direction of rotation of the cleaner flywheel 4″ is such that dust and impurities from the doffer roller at the interface between the doffer roller and the cleaner flywheel 4″ are sent in the opposite direction to that of the carding drum, the absolute value of the peripheral speed of the flywheel 4″ being greater that of the doffer roller 3′. According to the invention, a screen is provided, in particular in the form of an enclosure 11 arranged so as to prevent impurities and dust removed from the doffer roller 3′ by the cleaner flywheel 4″ from falling on the stripper roller 7′, thus preventing these impurities and dust from contaminating the fleece of fibres formed by the device.

FIG. 4 shows yet another method of implementation of a device according to the invention in which a drum cleaner flywheel is not provided. The device comprises a carding drum 1, upper and lower doffer rollers 3, 3′, two associated stripper rollers 7, 7′ and two doffer cleaner flywheels 4, 4′. An airtight roller 10 with rigid seal is also fitted between the carding drum and the upper doffer roller, below the doffer cleaner flywheel 4 to clean the flywheel 4 and recycle the dust and fibres from the carding drum and also preventing turbulence forming in the region between the drum and the upper doffer. In addition, an airtight roller 10′ with rigid seal is placed between the carding drum and the lower doffer roller. The device is completed by a traditional carding unit formed from a worker 21 and a sweeper 22.

In all methods of implementation, the airtight rollers 10, 10′, 10″ and the flywheel 9 rotate anticlockwise, in the opposite direction to the carding drum. However, these rollers can rotate in the same direction as the drum, in particular in the case of very dusty fibres to the point that they may not be captured by the airtight roller seals.

In the methods of implementation shown in FIGS. 1 and 2 , the smooth roller 5 rotates clockwise, in the same direction as the carding drum. However, this roller can rotate in the opposite direction to that of the drum as a function of the aerodynamic phenomena observed.

In the present invention, the, or each doffer roller immediately follows the carding drum (except for the fibres and/or the collected fleece which lies between them). In the same way, the stripper roller immediately follows the doffer roller (except for the fleece it is stripper from the doffer). On the other hand, the, or each output belt follows the doffer roller, but may be fitted between one or more rollers, in particular transfer rollers. 

1. A device for forming one or more fleece(s) of fibres by carding comprising a main carding drum supplied with raw fibres, one or more doffer roller(s) to collect fibres worked on the carding drum and an associated stripper roller to strip the fleece(s) of the fibres formed on the one or each more doffer roller(s) and deposit them later on one or more output belts, the device also comprising at least one doffer cleaner flywheel working with at least one doffer roller to remove dust and impurities, wherein prevention means are arranged so as to prevent dust and impurities removed from the doffer by the cleaner flywheel from escaping in the direction of the associated stripper roller.
 2. The device of claim 1, wherein the prevention means are that the doffer cleaner flywheel is driven in a direction such that the impurities or dust collected at a doffer cleaner flywheel/doffer roller interface are sent from the said interface directly to the main carding drum.
 3. The device of claim 1, wherein the doffer roller rotates in the opposite direction to the carding drum and the doffer cleaner flywheel rotates in the same direction as the carding drum.
 4. The device of claim 2, wherein the prevention means form a screen arranged between the interface and the stripper roller.
 5. The device of claim 1, wherein a carding drum cleaner flywheel is arranged upstream of the doffer roller.
 6. The device of claim 5, further comprising at least one downstream airtight roller downstream of the drum cleaner flywheel, the at least one or two airtight roller and the carding drum cleaner flywheel rotating in the same direction.
 7. The device of claim 6, wherein the downstream airtight roller is arranged to brush the doffer cleaner flywheel.
 8. The device of claim 5, further comprising an intermediate roller arranged between the carding drum and the doffer roller, so that it fills the vacuum causing turbulence that entrains accumulations of fibres and dust likely to be the source of faults in the fleece formed.
 9. The device of claim 8, wherein the intermediate roller is located below the downstream airtight roller.
 10. The device of claim 1, comprising two doffer rollers, upper and lower respectively, two respective upper and lower doffer cleaner flywheels, two respective upper and lower stripper rollers and an additional drum cleaner flywheel arranged upstream of the upper doffer roller and at least one downstream upper airtight roller downstream of the drum cleaner flywheel.
 11. The device of claim 10, wherein the upper doffer flywheel cleaner rotates in the opposite direction to the upper doffer roller and the lower doffer cleaner flywheel rotates in the opposite direction to the lower doffer roller.
 12. The device of claim 10, comprising an intermediate roller arranged between the main carding drum and the upper doffer roller, below the upper doffer cleaner flywheel and below the upper downstream airtight roller.
 13. The device of claim 10, comprising a lower airtight roller arranged between the lower doffer cleaner flywheel and the main carding drum, the lower airtight roller being used to brush the lower doffer cleaner flywheel.
 14. The device of claim 4, wherein the screen is in the form of an enclosure essentially surrounding the doffer cleaner wheel.
 15. The device of claim 6, which comprises two airtight rollers, downstream and upstream, respectively of the drum cleaner flywheel.
 16. The device of claim 15, wherein the one or the airtight rollers rotates in opposite direction to the carding drum.
 17. The device of claim 8, wherein the intermediate roller is arranged below the downstream airtight roller.
 18. The device of claim 10, which comprises two upper airtight rollers, downstream and upstream respectively of the drum cleaner flywheel.
 19. The device of claim 11, which comprises two doffer rollers which rotate in the same direction.
 20. The device of claim 13, wherein the lower airtight roller rotates in the opposite direction to the lower doffer cleaner flywheel. 